1. Field of Invention
This invention is an improved on demand media web electrophotographic printer with a feeding and cutting registration apparatus, including a method that reliably monitors and controls consistent media web feeding, registration, and the cutting of the web by utilizing a sensor system that includes a web buckle sensor to form a precise web buckle prior to each feeding and cutting. Utilizing a gap or indicia sensor, the processor accurately positions media, including media edges and performs a unique, more productive; automatic on-line operating setup of the media web with the cutting of each desired length. An improved initial setup of the roll of plain media, including adhesive backed media web spaced on a xe2x80x9cbackerxe2x80x9d roll for minimizing downtime and media wastage.
2. Description of Prior Art
On demand prior art printer apparatus, such as thermal transfer, address the technical problem of maintaining media web feeding and accurate printing without wastage by integrating into the apparatus, complex sensing and web compensation means, with the cutting of the web following printing. This thermal printer cutting method does not aid in the on line maintaining of the accuracy of registration. With thermal transfer, the printer automatic sensing and compensation means may frequently stop the printing operation to off-line adjust the media web and to more accurately position the media leading edge and media gap or indicia prior to printing. This level of complexity requires additional downtime for the operating setup of media printing which increases cost, lowers productivity, and reduces reliability. Also, there is much more downtime in the frequent changing of low capacity, high cost thermal media ribbons at greater expense than the electrophotographic (EP) printer high capacity toner cartridge of the present invention.
The present invention relates to the industrial marking market and the kind of on demand printer that generally uses media web special Printouts or non-standard sheet sizes, as opposed to the office document printers and copiers, which use a series of standard sheet sizes starting with 8.5xe2x80x3xc3x9711xe2x80x3. Industrial marking media web Printouts vary in length and width for text information and images related to transactions, data, identification, and includes photos, barcodes, labels, tags, tickets, narrow web receipts, and the like. Industrial marking also includes special cut sheet sizes for color labels, airline tickets, RFID tags, ID cards with photos, credit cards, and the like. These special cut sheet sizes may be web cut, and they may be web processed or separately handled in cut sheet feeders and stackers. The completed Printouts may be laminated in clear plastic. Industrial marking Printouts include xe2x80x9cspot colorsxe2x80x9d or full-color, i.e. yellow, magenta, cyan, and black.
On demand prior art industrial marking printers such as thermal transfer media web printers are designed to operate with a variety of media types, including pressure sensitive, die-cut, butt-cut, or stock media web. The type of media sensors the printer has, dictates its ability to operate with certain media types. Unless the media is a plain continuous web, die cuts, black marks, or notches help the printer determine the top of the media.
Thermal transfer printers come equipped with a variety of media sensors that enable the printer to gauge fixed vertical media length during the media calibration process. Automatic Off Line Calibration is a process that is typically performed by a web thermal transfer media printer in order to gauge the length of the media material loaded within it and compensate for error build up from repeated print cycles. Sensors within the printer""s media compartmentxe2x80x94commonly located around the thermal printheadxe2x80x94detect either the white spaces (inter-media gaps) or black marks and/or notches on the reverse side of the media stock that represent a media""s actual face size (length). Printer calibration ensures that the data is aligned and prints correctly on the media stock and is also cut correctly at the media gap or indicia after printing. The printer media sensors of the prior art may frequently stop printing to recalibrate off-line, resulting in excessive downtime and wasted media.
Prior art media web thermal printers are configured to contain any one of the below sensor varieties:
Transmissive Media Sensor is used to gauge media length for media with visible inter media gaps, notches, or pre-punched holes, or plain continuous media
Reflective Media Sensor is a reflective sensor emits light, which is reflected back to the sensor when it reaches an indicia or black mark.
Dual Media Sensors are two sensors within the printer (one reflective and one transmissive) that have the ability to detect both inter media gap and black mark media.
Multi-functional Sensor refers to a single sensor within the printer that has the ability to detect both inter media gap and black mark media, irrespectively.
EP printers are excellent at printing the highest quality bar code Media Web, text and graphics on plain paper media. Bar code density is also quite high on EP printers resulting in a scannable code at virtually any wavelength using an infrared scanner. However, widely used standard laser office page printers are not well suited for industrial media web applications. Here, they prove inadequate and wasteful, as it is impossible to produce single or small media lengths. (A minimum of at least xc2xd standard page of media is typically. required for the printer apparatus nips to maintain feeding control of the sheet. Unless the media is at least that size, the remainder is wasted). Since EP printers have been developed to process relatively long cut sheets, and continuous web EP applications tend to waste media when starting and stopping, electrophotographic technology has not been widely used for media web printing. In addition, the conventional EP apparatus (unlike the small footprint Media Web EP printer with very short media length capability of the present invention) has been developed with an inherently long media path of operating nips of subassemblies to accomplish the processes of latent imaging, toning, transfer, and fusing. A certain minimum length of the web is necessary to engage the nips of these prior art process units in order that a driving relationship in the printer is maintained. With current electrophotographic (EP) methods, the minimum length of a media sheet is limited by the allowable configuration, location or spacing of the nips between these operating subassemblies of the printer. As a result attempting to cut the media after the media is printed and is being ejected results in an overly long margin and waste of media.
Since EP printers have mechanically spread apart, functions of latent imaging, toning, and fusing, their web feeding and cutting apparatus must include means such as a web buckle of the media at the cutter to allow a clean severing of the stationary media, during the process of printing with precisely controlled leading and trailing edges without media wastage. However, unconstrained web feeding can result in an over size buckle causing a media jam. And, an undersize buckle does not allow enough time for a clean cut, resulting in irregular tearing and jamming of the media. Rapid printer response is required in most on demand applications, and it is desirable to have the web buckle formed ready for the print command. However, over a prolonged standby period, a permanent set of the web buckle may occur causing a media jam at the start of the next print cycle. These conditions are made worse by variations in the thickness and stiffness of the media.
The media web EP prior art discloses a web buckle accumulation apparatus and method for the control of the web unidirectional feeding and cutting during the printing process. EP web printers U.S. Pat. No. 3,639,053, and U.S. Pat. No. 5,768,675 disclose a web buckle accumulation method. With this method, the media web EP registration roll feed unit advances the web in an accurately timed relationship with the EP imaging unit, which may move slower than the media feed roll unit to accumulate a buckle between the two roll feed units. Dictated by the processor, on stopping the media feed roll unit at the desired length Printout, ahead of the EP imaging unit, the cutter cleanly severs the media web. The buckle flattens as the registration roll unit continues to feed the balance of the cut desired length through the latent imaging, developing, and fusing units of the EP printer. The cut defines the trailing edge of the desired media length and a new leading edge for the next print cycle. The processor controls the media printing, feeding and cutting to reduce media waste.
Another EP printer web feeding and cutting U.S. Pat. No. 5,708,345 has disclosed the use of a web buckle sensor to switch a motor from a feeding to a cutting mode. The web buckle is accumulated with a speed difference between two drivers of the EP Printer.
U.S. Pat. No. 4,025,187 discloses in a sheet fed EP printer, a cut sheet buckle that is formed rather than accumulated. The cut sheet buckle forming is controlled with digital clock reference time to obtain consistent skew removal and sheet separation from the cassette. The forming of the buckle is done by feeding the cut sheet forward to a stop, sensing the sheet leading edge, then feeding forward a set time interval to form the desired length buckle against the stop. No buckle sensor is applied to detect the buckle shape or size. The reference feeding time is made sufficient to form the desired buckle for the sole purpose of eliminating skew. The feeding time is adjustable for forming the buckle in order to take into account the slippage between the feeder and the sheet, and any error in the position of the leading edge of the sheet at the start of feed.
Another EP cut sheet printer disclosed in U.S. Pat. No. 3,241,831 forms a buckle against a stop under the control of a buckle sensor. After the appropriate buckle height is sensed the sheet is then fed in a conventional manner. Another U.S. Pat. No. 3,335,662 discloses the leading edge of the cut sheet buckle formed of a desired size against a fixed stop, as detected by a photoelectric sensor, or proximity sensor, starting the print cycle.
The prior art EP apparatus and methods do not teach, relate to or address the solutions required and the specialized needs of on demand small printers used in industrial marking, including high productivity, compact on demand media web label and transaction printing without wasting recording media, which historically has been a distinct development form EP office and document printers. It will be apparent from the Description of the Invention that the apparatus, methods, sensor system and control combinations required of the present EP invention discloses unique apparatus and methods for compact on demand EP printing, feeding and cutting that conserves media, lowers cost, and enhances productivity have not been anticipated by the prior art.
The on demand media web EP prior art does not disclose an improved media web registration apparatus and method for consistent precise registration for accurate media web feeding and locating of the desired media length leading edge; a sensor system with feedback to a processor that more effectively controls the imaging, printing, and the cutting web desired length prior to the completion of printing. In addition, the prior art does include an initial automatic setup of the media roll, followed by an on line operating""setup included in each print cycle that maintains the consistent quality of Printouts without downtime, thereby further increasing productivity, reducing cost and eliminating media wastage. The EP printer of the present invention discloses all have the above new apparatus and methods including full color EP printing.
Higher resolution (a finer dot size and increased dots per inch) is required to facilitate the printing of text, such as six point, and bar codes on small or miniaturized label media, such as commonly used in the electronics of pharmaceutical industries for component or specimen labels. The higher print resolution of the EP printer enable more detailed media (often highly miniaturized and compact) to be accomplished without impairing print quality and scanner readability. The Media Web Electrophotgraphic (EP) Printer has the advantage of superior photographic print quality with a much finer dot size or dot acuity, full-color graphics capability, with permanent print on plain media with the highest abrasive resistance. The new Media Web Electrophotgraphic (EP) Printer is significantly lower in media cost than direct thermal media, and a much higher capacity EP toner cartridge at lower cost with a lower frequency of replacement than printers such as impact ribbon, thermal transfer ribbon, and ink jet cartridge.
EP printer operation of the present invention takes place with an electronic processor, which includes a formatter and a controller. With a print command the formatter receives the print information from the interface with the host terminal based on the host protocol, and determines the printed output for the printer controller including the desired media length prior to printing. The formatter instantly translates the print information with commands for the controller to process the imaging, and to cut the media to the desired length. Instructed by the formatter on a print command from the host, the controller engages the registration rolls with a clutch to the main stepper motor. A synchronization sensor is located after and immediately adjacent to the nip between the registration rolls and at a predetermined fixed distance from the nip between the transfer roll and photosensitive drum. A registration roll nip sensor detects the leading edge of the media web at the nip between the registration rolls before forming the web buckle prior to the print operation. The web buckle is formed by a registration web guide is detected by a web buckle sensor. During printer operation and prior to cutting, the speed of the image processing registration rolls and media feed rolls are synchronized at the same speed to maintain the accurate web buckle formed before the start of the print cycle.
The laser diode beam scans the rotating photosensitive drum, or rotary image carrier, followed by the toned image on the drum. The point of image transfer to the media web is precisely at the nip between the transfer roll and photosensitive drum. As the toned image is transferred to the media web from the drum at the drum/transfer roll nip, the printed web is advanced through the fixing unit. The fixing of the toned image takes place between the nip of the fuser roll and the pressure roll of the fuser unit. The controller tracks the feeding of the media web until the length remaining of the total media desired length Printout determined by the formatter, equals the fixed distance from the synchronization sensor to the cutter. At this point, the controller stops the media feed unit and the media web ahead of the media feed rolls, is severed cleanly from the media roll by the cutter creating the desired length trailing edge, as the controlled web buckle flattens.
After the media feed unit is stopped and the cutter is actuated, the registration roll clutch remains engaged feeding the balance of the severed media through the EP printing unit until the synchronization sensor, signals the controller that the end of the media has passed the sensor. The image scanner stops after the media has traveled the required distance from the sensor to meet the end of print at the nip of the photosensitive drum and transfer roll. The main stepper motor continues to operate the imaging unit until the fuser exit sensor detects the trailing end of the media.
Once the trailing edge of the desired length Printout passes the synchronization sensor, the new web buckle may be formed between the cutter and the stopped registration roll nip by the media feed rolls. The imaging unit finishes the printing as the remainder of the desired length Printout is fed through the printer. While printing continues, the media feed rolls feed the media web leading edge forward the desired distance and length and then may form the accurate web buckle with the stopped upper registration roll and the registration web guide as ordered by the formatter and exercised by the controller for the each print job. Each time media web, or a group of media such as labels on a web backer, is printed and cut, the formatter instructs the controller to feed the web leading edge to the nip between the registration rolls to be made ready for the next print command.
The media feed rolls may be operated by the main printer motor through a clutch, or operated by a separate media feed roll motor, at the same drive speed as the printing process including registration rollers. In effect, the controller with single drive main motor clock synchronized with the image scanner simultaneously drives the web constantly with a first and second driver. The drives operate at the same time at the same speed to move the web except on web buckle setup at each Printout (registration driver stopped), and when cutting the web (media feed driver stopped).
The present invention relates to an improved Media Web Electrophotographic (EP) Printer, including an enhanced web feeding and cutting apparatus and method, which has a built-in accuracy renewal capability, utilizing a novel sensing system including a web buckle. Unlike the thermal printer and the EP prior art, the present invention provides the operating setup of the media web leading edge with a media gap or indicia sensor for accurate Registration while printing continues to take place, included in the normal online printer operation to enhance throughput and productivity.
It is desired that these kinds of printers and apparatus perform rapidly and reliably with unattended operation in terminals and the like, over an extended period of time. Therefore, the present invention to avoid the above limitations comprises feedback sensors included with the web feeding and cutting apparatus, and a processor to reliably form and maintain a precise adequate web buckle on demand in unattended operation. Each time a media is cut, the printer automatically on-line recalibrates and positions the leading edge of the web for the next print command, maintaining Registration accuracy without downtime and wasted media web.
Advantages of the new EP printer over thermal transfer and other comparable technologies include:
High contrast, crisp image bar code print quality with a durable, long-life and archival image stability with higher dot acuity and better abrasive resistance.
Improved batch or individual media print capabilityxe2x80x94without waste and downtime.
Lower, long-term maintenance, media and consumables cost.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, according to one aspect of this invention, a preferred compact electrophotographic printing apparatus including a print processor including a controller and a formatter containing sufficient memory for adequate image information to format the data to print the completed media. The formatter provides the Printout to the printer controller for each media of the desired length Printout for each print command from a host terminal.
The fast printing capability of laser and LED apparatus, allows the information to be held in the printer formatter memory for a correct total Printout, or an end of file command. Thus, the printer formatter, instantly communicating with the host terminal through a bi-directional interface, determines the complete media before printing starts with the controller. The printer formatter obtains the print job and separates it into efficient image formation to conserve media and instructions to control the printing process. For media web the formatter determines the complete desired length Printout from the host prior to the start of its hardcopy output. In summary, the formatter receives and processes the print data from the terminal or host interface, then develops and coordinates data placement and timing with the printer engine controller. The controller receives from the formatter, the information and data in the form that it needs to operate the printer. The controller then immediately synchronizes the image formation system with toning, fusing, and media feeding systems, including web cutting. The controller when ready, then signals the formatter to send the print image data.
Formatting time is the time required to convert the program to an image on the media. Depending on the complexity and size of the barcode media format and the printer""s ability to process this information in an efficient manner, media-formatting time can sometimes cause a delay in printing, affecting a printer""s overall print speed capability. Such delays can be annoying as well as costly if they occur in a production environment where time and on-demand print capability are of the essence. They must begin printing the desired media image even before the media format processing is complete. However, the formatter instantly receives the complete media data from the host with all of the information to be printed at the desired media length, before interacting with the controller to cause printing and cutting to take place, and allows the host instantly check the media information for accuracy and make corrections, before printing the complete media. The timing control of the present invention is accomplished in the same manner, but with a more productive and cost effective method of on line calibration of media web with accurate, reliable web feeding and cutting.
A novel serial full color EP printhead of the present invention provides fast color printing of the media web. Furthermore, a novel media web traversing serial full color EP printhead, compared to the prior art traversing serial full color ink jet, has a much wider print image width of the traversing print scan. The fewer scan passes of the traversing serial EP printhead of the present invention complete a document more rapidly, in the order of ten times faster. This traversing serial EP printhead capability also allows both narrow and wide format graphics printing of large page sizes in all four colors, yellow, magenta, cyan, and black serially at lower cost of toner consumables.
This improved on demand Media Web Electrophotographic (EP) Printer includes a Registration apparatus that monitors and controls accurate web feeding, cutting and locating of the web desired length printout leading and trailing edges for printing. The improved EP printer also detects media gaps or indicia, determines media spacing and Registration, and defines a controlled minimum length web buckle with a sensing means that forms the precise buckle prior to feeding and cutting. Additionally, the present invention also includes a process of on line operating setup and control of the feeding and cutting apparatus to assure a repeatable and reliable media printing operation to reduce downtime and minimize wastage. Furthermore, the improvement synchronizes the registration and feed rolls, in combination with the simple sensing means, allowing for control of the media web by forming the precise web buckle repeatedly and reliably after cutting on line, and during a media web feed operating setup procedure with the registration rolls stopped. The new and improved registration apparatus provides a unique, rapid thru-put, cost-effective module for laser or LED printing technology, but is adaptable as well to other printers such as direct thermal, thermal transfer, and ink jet.
The present invention has solved the minimum media and length limitations of electrophotographic printers and provides a unique, cost-effective small footprint laser or LED printing apparatus for continuous media web printing with a rapid, reliable, and simple method of feeding and severing the web desired length printout prior to the completion of EP printing.
It is therefore a primary object of the present invention to provide an improved, more reliable media web feeding and cutting apparatus with feedback, which repeatedly forms an optimum and repeatable web buckle for more accurate synchronization of the printing and cutting of the media web.
It is a further object of this invention to provide a more reliable web feeding and cutting apparatus, which repeatedly senses the web leading edge at a registration roll nip, pre-forms an accurate and optimum web buckle prior to printing utilizing a pivoting registration web guide in conjunction with a web buckle sensor.
It is a further object of this invention to provide an improved on line operating setup in the normal operating sequence of the printing process to enhance productivity by saving the prior art additional downtime off-line of the printing process to accomplish the setup of the media web for accurate registration.
It is a further object of this invention to provide accuracy of web feeding and cutting to consistently or repeatedly obtain an accurate desired length printout.
It is a further object of this invention to provide accuracy of web feeding and cutting utilizing narrow and standard media web and media sensors.
It is a further object of this invention to provide consistent feeding and cutting with an optimum but minimum web buckle, whereby the desired length cannot flip back, and interfere with the next media, tending to cause a media jam during feeding.
It is a further object of this invention to provide improved monitoring and control of the web buckle with a web buckle sensor before the latent imaging unit whereby the media web is in accurate and repeatable registration for printing and cutting.
It is a further object of this invention to provide an optimized apparatus and method for monitoring and controlling feeding and cutting for the differences in media characteristics.
It is a further object of this invention to provide a method that avoids maintaining a web buckle for a prolonged period that may cause a permanent set in media stock that may cause a possible media jam.
It is therefore a primary object of the present invention to provide a printing apparatus and method, with a high cartridge capacity, and a low cost of consumables.
It is another object of this invention to provide a printing apparatus with an improved processor with a sensor system that provides effective feedback and consistently controls the media desired length.
It is another object of this invention to provide a small, narrow and standard format EP printing apparatus, which accurately controls, prints and dispenses short, closely spaced media web.
It is a further object of this invention to provide a high print quality apparatus, which is designed to occupy a very small footprint area as a palm size printer for portable and wireless terminal applications.
It is a further object of this invention to provide a more reliable media web printing apparatus which images the input data, transfers the image to the recording medium, fuses the toner image, stops the recording medium roll, and automatically cuts the media web to any desired length.
It is a further object of this invention to provide an on demand compact narrow format printer for portable and wireless applications, which is designed to accept various media including cut plastic sheets, and smart cards as well as specialty paper.
It is a further object of this invention to provide an on demand narrow format fullcolor laser or LED printhead, which is designed to accept various media such as both narrow and wide media web roll, continuous forms, cut sheets and card stock for packaging, including transactions and barcode labels.
It is a further object of this invention to provide an on demand full-color printer whereby a laser or LED serial printhead transverses the media web, and which is designed to accept various media such as both narrow and wide media web roll, continuous forms, cut sheets and card stock for packaging, including transactions and barcode labels.
It is a further object of this invention to provide an on demand laser or LED printer with a high speed flash fuser which is designed to accept various media such as both narrow and wide media web roll, continuous forms, cut sheets and card stock for packaging, including transactions and barcode labels.
Other features and advantages of the present invention will become readily apparent from the following description taken in conjunction with the accompanying drawings.